Do Light Bulbs Give Off Heat?
Most people don't take notice of light bulbs. At best, they take them for granted, not being concerned with any aspect of their operation other than the fact that it's either on, off or broken. Light bulbs give off heat as well as light. This is a byproduct of the process that powers the light bulb. Nearly all light bulbs shed excess heat, with some generating less heat than others.
Light Bulb Heat
Have you ever put your hand close to a lit bulb? If you have, then you'd know that light bulb heat up when in operation. Depending on the type of light bulb used, the amount of heat given off will vary. In order to better understand how excess heat correlates to energy efficiency, just remember that the more excess heat a bulb gives off, the less wattage is being used to provide light and as a consequence, the less efficient the bulb is operating. Incandescent bulbs are notorious for being inefficient when it comes to generating light, instead generating the vast majority of wattage as excess heat. In most cases, only 5% of wattage is converted into actual light. That leaves 95% of the energy used by an incandescent light bulb being wasted as excess heat.
On the other hand, compact fluorescent lights (CFL) and light emitting diodes (LED) are a bit more efficient and as a result, generate less excess heat. Anywhere from 25% to 28% of the wattage generated by a CFL is converted into actual light, while the rest is expended as excess heat. Some types of LED bulbs generate their fair share of heat, which is why some of the more powerful applications require integrated heat sinks in order to draw away excess heat. Most other LED bulbs generate very little heat in comparison to CFL and LED bulbs. This means that little energy is being wasted as heat, making LED bulbs more efficient than CFL and incandescent light bulbs.
Why Do Light Bulbs Produce Heat?
All light bulbs require some sort of electric current of the proper voltage in order to operate. In the case of the incandescent light bulb, this current is delivered to the bulb, where it passes through a filament made of tungsten wire. The filament is heated to a temperature of between 3100 to 5400 degrees Fahrenheit thanks to the electric current. This is below the filament's melting point of 6192 degrees Fahrenheit, so the filament is not in danger of burning out short of its lifespan. However, the constant heat causes the filament to wear down, resulting in the filament's fracture at the end of its life cycle.
The amount of heat given off depends on the type of the filament, its size and shape, plus the amount of current passing through. The more current that passes through a filament, the more heat it generates. Considering that over 90% of that current is wasted as heat, this means that an incandescent light bulb can become rather hot. Heat from the filament is quickly transferred to the outer glass bulb, causing the bulb itself to reach a temperature of between 400 and 550 degrees Fahrenheit. Light bulbs used for industrial applications can reach even higher temperatures. When operating such lights, extra precautions must be taken in order to prevent any possible fire hazard.
How to Reduce Excess Heat
If you are concerned that your light bulbs are creating too much heat, then there are actions you can take to not only reduce that amount of excess heat, but also make your home or office more energy efficient and safe from fire hazards. One affordable way to take action is to use a lower bulb wattage. 60 watt light bulbs tend to produce less heat than their 75 and 100 watt counterparts. Keep in mind that when you switch to bulbs of a lower wattage, you may the lower the amount of heat given off, but you'll also lower the amount of light that is produced.
Another way to reduce heat is to make sure that the right bulb is used for the right socket. Some applications, such as reading lamps and bathroom lights, require bulbs of a lower wattage. Using higher wattage light bulbs in these cases can not only cause more excess heat, but they can also become a potential fire hazard. If there is too much current being drawn to the bulb, the wiring leading to the socket can potentially burn out or the bulb can arc, causing wiring damage or fire.
You can also switch to CFLs and LED lighting. These types of lighting produce far less heat than incandescent bulbs while producing the equivalent amount of light. Keep in mind that while the amount of heat produced is lowered, these bulbs still generate excess heat. In the case of CFLs, excess heat can be produced by the bulb's electronic ballast, attached to the bulb itself. The ballast regulates the amount of current allowed to flow through the bulb. This part can generate excess heat, so care must be taken in the placement of CFL lights.
More Light Bulb Questions